Trans unsaturated fatty acids are produced commercially in large quantities by heating vegetable oils in the presence of metal catalysts and hydrogen to form shortening and margarine.1 They are so named because the carbon atoms adjacent to their double bonds are on opposite sides, resulting in a straight configuration and a solid state at room temperature. In contrast, naturally occurring unsaturated fatty acids contain double bonds as cis isomers, with adjacent carbons on the same side of the double bond, resulting in a bent shape and a liquid state at room temperature. Partial hydrogenation, the process used to create . . .